This invention relates to 2,5-bisalkloxyterephthalic acid and to a method for preparing these compounds.
There is a current need for acid stable, amorphous, high molecular weight polymers for use as theremoplastic matrices in molecular composites. The thermoplastics previously used generally show poor compatibility with aromatic heterocyclic rigid rod polymers due to differences in structure. These previously used theremoplastics also generally have high glass transition temperatures or melting points, thus making them difficult to consolidate into molecular composites.
The present invention provides dicarboxylic acid monomers with long alkyloxy pendant groups which, when polymerized with an appropriate bis-o-aminophenol monomer, provide polybenzoxazole polymers with glass transition temperatures below about 100.degree. C. The structural similarity of the aromatic heterocyclic backbone of such polymers helps increase compatibility with aromatic heterocyclic rigid rod polymers.
Accordingly, it is an object of this invention to provide dicarboxylic acid monomers with long alkyloxy pendant groups.
It is another object of this invention to provide a method for preparing these monomers.
Other objects and advantages of the present invention will be apparent to those skilled in the art.